安徽桂花冲铜矿床地质与成矿流体地球化学

发布时间：2018-03-06 02:30

  本文选题：矿床地质　切入点：成矿流体地球化学　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：安徽桂花冲铜矿床位于铜陵矿集区沙滩脚矿田内,是一个新发现的以发育斑岩型矿体为主的斑岩-矽卡岩复合型铜矿床。该矿床在产出位置和矿床类型方面均有别于铜陵矿集区以矽卡岩型为主的其它矿床。本文通过野外调查与室内分析研究,查明了桂花冲铜矿床的地质特征以及斑岩型矿体成矿流体地球化学特征,并探讨了其成矿流体的来源、演化及成矿过程。桂花冲铜矿床的蚀变矿化具有明显的空间分带特征,自斑岩体向地层依次出现花岗闪长斑岩、钾化带、黄铁绢英岩化带、高岭土化带、青磐岩化带、矽卡岩化带以及大理岩。矿体赋存于斑岩体内部及斑岩体与大理岩的接触带内。考虑到矽卡岩期矿化不发育,本文主要对斑岩期成矿过程展开研究,根据地质体相互穿插关系和矿物共生组合特征可将斑岩期蚀变矿化过程划分为钾化、绢英岩化、石英黄铁矿、石英多金属硫化物和碳酸盐五个阶段。流体包裹体的研究显示,绢英岩化阶段主要发育纯气体包裹体、含子矿物包裹体及富气相包裹体,石英黄铁矿阶段主要发育纯气体包裹体、含子矿物包裹体、富气相包裹体及富液相包裹体,石英多金属硫化物阶段以及碳酸盐阶段主要发育富液相包裹体。从早期绢英岩化阶段到晚期碳酸盐阶段,成矿流体经历了从高温(472.9℃)、高盐度(47.7~67.9%Na Cleqv.)向中低温(140.2℃~280.3℃)、低盐度(1.6~7.7%Na Cleqv.)的持续演化。成矿压力主要集中在1.0~49.0MPa,对应的成矿深度为0.6~2.0km。氢氧同位素分析表明,早期成矿流体主要以岩浆热液为主,晚期则明显有大气降水的加入。成矿过程中流体经历了沸腾作用及混合作用,其中岩浆热液与大气降水的混合作用是导致成矿物质沉淀的主要机制。
[Abstract]:The Guihuachong copper deposit in Anhui Province is located in the Xiaodao Orefield in Tongling Ore concentration area. It is a newly discovered porphyry skarn complex copper deposit, which is mainly developed porphyry orebody. The deposit is different from other ore deposits in occurrence location and deposit type in Tongling ore concentration area, which is dominated by skarn type. Through field investigation and indoor analysis, The geological characteristics of Guihuachong copper deposit and the geochemical characteristics of ore-forming fluid of porphyry orebody are found out, and the origin, evolution and metallogenic process of ore-forming fluid are discussed. The alteration mineralization of Guihuachong copper deposit has obvious spatial zonation characteristics. There are granodiorite porphyry zone, kalitization zone, Huangtiequanite zone, kaolinization zone, Qingpan petrolization zone, etc. The orebodies occur in porphyry body and contact zone between porphyry and marble. Considering that the mineralization of skarn period is not developed, the ore-forming process of porphyry period is studied in this paper. The porphyry alteration and mineralization process can be divided into five stages according to the interpenetrating relationship of geological bodies and mineral symbiotic assemblages. The study of fluid inclusions shows that the alteration and mineralization processes of porphyry epoch can be divided into five stages: potassium, sericite, quartz pyrite, quartz polymetallic sulphide and carbonate. The pure gas inclusions are mainly developed in the sericite stage, the submineral inclusions and the gas-rich inclusions are mainly developed, while the pure gas inclusions, the submineral inclusions, the gas-rich inclusions and the liquid-rich inclusions are mainly developed in the quartz pyrite stage. The quartz polymetallic sulphide stage and carbonate stage are mainly rich in liquid inclusions, from the early sericite stage to the late carbonate stage, The ore-forming fluid has undergone a continuous evolution from high temperature (472.9 鈩，

本文编号：1572963